AnimTestbed/3rdparty/imgui-node-editor/examples/blueprints-example/utilities/builders.cpp

//------------------------------------------------------------------------------
// LICENSE
//   This software is dual-licensed to the public domain and under the following
//   license: you are granted a perpetual, irrevocable license to copy, modify,
//   publish, and distribute this file as you see fit.
//
// CREDITS
//   Written by Michal Cichon
//------------------------------------------------------------------------------
# define IMGUI_DEFINE_MATH_OPERATORS
# include "builders.h"
# include <imgui_internal.h>


//------------------------------------------------------------------------------
namespace ed   = ax::NodeEditor;
namespace util = ax::NodeEditor::Utilities;

util::BlueprintNodeBuilder::BlueprintNodeBuilder(ImTextureID texture, int textureWidth, int textureHeight):
    HeaderTextureId(texture),
    HeaderTextureWidth(textureWidth),
    HeaderTextureHeight(textureHeight),
    CurrentNodeId(0),
    CurrentStage(Stage::Invalid),
    HasHeader(false)
{
}

void util::BlueprintNodeBuilder::Begin(ed::NodeId id)
{
    HasHeader  = false;
    HeaderMin = HeaderMax = ImVec2();

    ed::PushStyleVar(StyleVar_NodePadding, ImVec4(8, 4, 8, 8));

    ed::BeginNode(id);

    ImGui::PushID(id.AsPointer());
    CurrentNodeId = id;

    SetStage(Stage::Begin);
}

void util::BlueprintNodeBuilder::End()
{
    SetStage(Stage::End);

    ed::EndNode();

    if (ImGui::IsItemVisible())
    {
        auto alpha = static_cast<int>(255 * ImGui::GetStyle().Alpha);

        auto drawList = ed::GetNodeBackgroundDrawList(CurrentNodeId);

        const auto halfBorderWidth = ed::GetStyle().NodeBorderWidth * 0.5f;

        auto headerColor = IM_COL32(0, 0, 0, alpha) | (HeaderColor & IM_COL32(255, 255, 255, 0));
        if ((HeaderMax.x > HeaderMin.x) && (HeaderMax.y > HeaderMin.y) && HeaderTextureId)
        {
            const auto uv = ImVec2(
                (HeaderMax.x - HeaderMin.x) / (float)(4.0f * HeaderTextureWidth),
                (HeaderMax.y - HeaderMin.y) / (float)(4.0f * HeaderTextureHeight));

            drawList->AddImageRounded(HeaderTextureId,
                HeaderMin - ImVec2(8 - halfBorderWidth, 4 - halfBorderWidth),
                HeaderMax + ImVec2(8 - halfBorderWidth, 0),
                ImVec2(0.0f, 0.0f), uv,
#if IMGUI_VERSION_NUM > 18101
                headerColor, GetStyle().NodeRounding, ImDrawFlags_RoundCornersTop);
#else
                headerColor, GetStyle().NodeRounding, 1 | 2);
#endif

            if (ContentMin.y > HeaderMax.y)
            {
                drawList->AddLine(
                    ImVec2(HeaderMin.x - (8 - halfBorderWidth), HeaderMax.y - 0.5f),
                    ImVec2(HeaderMax.x + (8 - halfBorderWidth), HeaderMax.y - 0.5f),
                    ImColor(255, 255, 255, 96 * alpha / (3 * 255)), 1.0f);
            }
        }
    }

    CurrentNodeId = 0;

    ImGui::PopID();

    ed::PopStyleVar();

    SetStage(Stage::Invalid);
}

void util::BlueprintNodeBuilder::Header(const ImVec4& color)
{
    HeaderColor = ImColor(color);
    SetStage(Stage::Header);
}

void util::BlueprintNodeBuilder::EndHeader()
{
    SetStage(Stage::Content);
}

void util::BlueprintNodeBuilder::Input(ed::PinId id)
{
    if (CurrentStage == Stage::Begin)
        SetStage(Stage::Content);

    const auto applyPadding = (CurrentStage == Stage::Input);

    SetStage(Stage::Input);

    if (applyPadding)
        ImGui::Spring(0);

    Pin(id, PinKind::Input);

    ImGui::BeginHorizontal(id.AsPointer());
}

void util::BlueprintNodeBuilder::EndInput()
{
    ImGui::EndHorizontal();

    EndPin();
}

void util::BlueprintNodeBuilder::Middle()
{
    if (CurrentStage == Stage::Begin)
        SetStage(Stage::Content);

    SetStage(Stage::Middle);
}

void util::BlueprintNodeBuilder::Output(ed::PinId id)
{
    if (CurrentStage == Stage::Begin)
        SetStage(Stage::Content);

    const auto applyPadding = (CurrentStage == Stage::Output);

    SetStage(Stage::Output);

    if (applyPadding)
        ImGui::Spring(0);

    Pin(id, PinKind::Output);

    ImGui::BeginHorizontal(id.AsPointer());
}

void util::BlueprintNodeBuilder::EndOutput()
{
    ImGui::EndHorizontal();

    EndPin();
}

bool util::BlueprintNodeBuilder::SetStage(Stage stage)
{
    if (stage == CurrentStage)
        return false;

    auto oldStage = CurrentStage;
    CurrentStage = stage;

    ImVec2 cursor;
    switch (oldStage)
    {
        case Stage::Begin:
            break;

        case Stage::Header:
            ImGui::EndHorizontal();
            HeaderMin = ImGui::GetItemRectMin();
            HeaderMax = ImGui::GetItemRectMax();

            // spacing between header and content
            ImGui::Spring(0, ImGui::GetStyle().ItemSpacing.y * 2.0f);

            break;

        case Stage::Content:
            break;

        case Stage::Input:
            ed::PopStyleVar(2);

            ImGui::Spring(1, 0);
            ImGui::EndVertical();

            // #debug
            // ImGui::GetWindowDrawList()->AddRect(
            //     ImGui::GetItemRectMin(), ImGui::GetItemRectMax(), IM_COL32(255, 0, 0, 255));

            break;

        case Stage::Middle:
            ImGui::EndVertical();

            // #debug
            // ImGui::GetWindowDrawList()->AddRect(
            //     ImGui::GetItemRectMin(), ImGui::GetItemRectMax(), IM_COL32(255, 0, 0, 255));

            break;

        case Stage::Output:
            ed::PopStyleVar(2);

            ImGui::Spring(1, 0);
            ImGui::EndVertical();

            // #debug
            // ImGui::GetWindowDrawList()->AddRect(
            //     ImGui::GetItemRectMin(), ImGui::GetItemRectMax(), IM_COL32(255, 0, 0, 255));

            break;

        case Stage::End:
            break;

        case Stage::Invalid:
            break;
    }

    switch (stage)
    {
        case Stage::Begin:
            ImGui::BeginVertical("node");
            break;

        case Stage::Header:
            HasHeader = true;

            ImGui::BeginHorizontal("header");
            break;

        case Stage::Content:
            if (oldStage == Stage::Begin)
                ImGui::Spring(0);

            ImGui::BeginHorizontal("content");
            ImGui::Spring(0, 0);
            break;

        case Stage::Input:
            ImGui::BeginVertical("inputs", ImVec2(0, 0), 0.0f);

            ed::PushStyleVar(ed::StyleVar_PivotAlignment, ImVec2(0, 0.5f));
            ed::PushStyleVar(ed::StyleVar_PivotSize, ImVec2(0, 0));

            if (!HasHeader)
                ImGui::Spring(1, 0);
            break;

        case Stage::Middle:
            ImGui::Spring(1);
            ImGui::BeginVertical("middle", ImVec2(0, 0), 1.0f);
            break;

        case Stage::Output:
            if (oldStage == Stage::Middle || oldStage == Stage::Input)
                ImGui::Spring(1);
            else
                ImGui::Spring(1, 0);
            ImGui::BeginVertical("outputs", ImVec2(0, 0), 1.0f);

            ed::PushStyleVar(ed::StyleVar_PivotAlignment, ImVec2(1.0f, 0.5f));
            ed::PushStyleVar(ed::StyleVar_PivotSize, ImVec2(0, 0));

            if (!HasHeader)
                ImGui::Spring(1, 0);
            break;

        case Stage::End:
            if (oldStage == Stage::Input)
                ImGui::Spring(1, 0);
            if (oldStage != Stage::Begin)
                ImGui::EndHorizontal();
            ContentMin = ImGui::GetItemRectMin();
            ContentMax = ImGui::GetItemRectMax();

            //ImGui::Spring(0);
            ImGui::EndVertical();
            NodeMin = ImGui::GetItemRectMin();
            NodeMax = ImGui::GetItemRectMax();
            break;

        case Stage::Invalid:
            break;
    }

    return true;
}

void util::BlueprintNodeBuilder::Pin(ed::PinId id, ed::PinKind kind)
{
    ed::BeginPin(id, kind);
}

void util::BlueprintNodeBuilder::EndPin()
{
    ed::EndPin();

    // #debug
    // ImGui::GetWindowDrawList()->AddRectFilled(
    //     ImGui::GetItemRectMin(), ImGui::GetItemRectMax(), IM_COL32(255, 0, 0, 64));
}